Field of the Invention
The present invention relates to a lightweight board having an upper covering layer, which extends in a longitudinal direction, having a lower covering layer, which extends parallel to the upper covering layer and is spaced apart from the upper covering layer in a direction perpendicular to the longitudinal direction, having a light middle layer, which extends between the upper covering layer and the lower covering layer, and having a bar, which extends between the upper covering layer and the lower covering layer and consists of wood or wood-based material. The invention also relates to a connection arrangement comprising such a lightweight board and comprising a further component. The invention finally relates to a method for producing such a connection arrangement.
Description of Related Art
Lightweight boards have been known from the prior art for a long time. They have an upper and a lower covering layer and a light middle layer, that is, a middle layer consisting of a material of a lower density than the covering layers, arranged therebetween. Lightweight boards have been used for a long time in many different ways, especially in furniture and interior construction.
Lightweight boards are used inter alia in the field of high-class fittings, especially in furniture construction, because their use allows very large wall thicknesses to be realised, which offer particular design possibilities. Recently, lightweight boards have also been used in mass-produced furniture, so even use on a broader scale is economically possible. The different advantages of the lightweight boards are thus accessible to a larger class of end users.
Lightweight boards are also increasingly being produced industrially. To this end, a light middle layer is provided with the covering layers, usually by adhesive bonding, so that a large-format composite is produced. Depending on the required stability of the board, covering layers of different thicknesses are used, usually consisting of a wood-based material such as a chipboard, fibreboard or OSB board. The boards used can be already coated, that is, provided for instance with a laminate, a paint, a print with a seal, a melamine resin layer, a veneer etc. Honeycomb cardboard or foam boards consisting of expanded plastic are preferred as the middle layers. Honeycomb materials consisting of materials other than cardboard may also be sensible for certain purposes. Extremely thin board materials or else thin metal, for example consisting of aluminum, can be used for this. It is however also possible to use lightweight wood-based materials such as appropriate chipboards or fibreboards or else solid wood of low density such as balsa wood as the middle layers. In principle all materials are possible for use as the light middle layer if provided with corresponding recesses/cavities. For instance, wood types are also used that do not have a particularly low weight but are easily available and can be worked well with cutting tools.
For stability reasons, so called bars can be inserted between the covering layers at one or more end faces of a lightweight board, said bars usually consisting of a wood-based material and being able to absorb relatively large compressive forces perpendicular to the board plane. A plurality of bars can also be connected to each other to form a frame. Such a bar generally has a rectangular cross section in a section perpendicular to the board plane and generally runs over the entire width (transverse bar) or over the entire length (longitudinal bar) of the lightweight board. Such bars or frames prevent the light middle layer, which often consists of cardboard webs, from being damage in the event of high compressive loading perpendicular to the board plane.
Lightweight boards of the above-described type and having the described features also form the basis of the present invention. This applies in particular to the described materials of the covering layers and of the middle layer.
Furniture is very often produced from wood-based materials such as the chipboards or fibreboards already mentioned. The individual elements or boards are usually connected by means of screw fastenings, dowels, various carcass connectors, adhesive bonding or combinations thereof.
The connections usually used in the prior art are realised by means of the described fitting parts (screw fastenings, dowels etc.). These have a number of disadvantages: they entail considerable costs, tools are needed for assembly, the end user generally required a certain amount of practice if assembling a piece of furniture himself, he does not have optimal tools or suitable retaining devices, he must use muscular force and therefore exert himself physically if there are several items of furniture, so that the furniture can easily be damaged or the end user can injure himself if he is unused to such activities. A further problem is that fitting parts are often missing from the package containing the furniture parts, as a result of which the end user is forced to obtain replacements from the vendor. Moreover, assembly by the end user causes undesirable dirtying, for example owing to glue residues, dust, chippings etc. After assembly is complete, the end user must therefore clean the assembly site and clear away the tools.
Furniture is also known from the prior art that can be assembled by angling (i.e. a pivoting movement) and/or snapping (i.e. latching) the furniture parts or boards to be connected to each other by means of corresponding profiles having mechanical locking elements. Such a connection is also referred to as a click connection. Furniture assembled in this manner offer a certain improvement. However, such solutions require a solid material of significant thickness as the board material, since sufficiently stable profiles can be produced only in this manner. The connection arrangements produced therefrom and consequently the furniture produced therefrom are therefore comparatively heavy and difficult to handle. The assembler, who as an end user generally lacks practice, must therefore handle a relatively high weight both during transport and during assembly, which often requires the assistance of an additional person.
DE 10 2007 007 832 A1 discloses a panel that consists of a sandwich structure having two covering layers, two honeycomb layers and an intermediate layer arranged between the honeycomb layers. This is also a lightweight board within the meaning of the present invention, the two honeycomb layers and the intermediate layer together forming the middle layer. The intermediate layer consists of a wood-based material and has a tongue profile on one side and a groove profile on the other side. The tongue profile consists of a projection in the form of an arrowhead (FIG. 1, item 14), the groove profile is formed in a manner complementary thereto (negative shape). Two panels can be connected to each other by joining a tongue profile to a corresponding groove profile of another panel of the same type. The profiles, i.e. the tongue profile and the groove profile, are formed in such a manner that mechanical locking, that is, a form fit, is provided in the longitudinal direction (direction of the board plane) and in the direction perpendicular to the longitudinal direction (direction perpendicular to the board plane). Such panels are however only suitable for producing flat panelling or flat surfacing.